Head assembly for grab buckets



Aug. 29, 1939. E. HARRINGTON I I I HEAD ASSEMBLY FOR GRAB BUCKETS 2 Sheets-Sheetl Fild Oct. 27, 1938 INVENTOR Edward L.Harr-l'n'g'fon 4; my 1 i d/ wzl Aug. 29, 1939. E. HARRINGTON v HEAD ASSEMBLY FOR GRAB BUCKETS Filed 001. 27, 1938 2 Sheets-Sheet 2 INVENTOR Edward L.. Harrin 9 fan Patented Aug. 29, 1939 UNITED STATES PATENT OFFICE HEAD ASSEMBLY FOR GRAB BUCKETS Application October 27, 1938, Serial No. 237,252

6 Claims.

This invention relates to a hoisting bucket such as a clamshell or other type of grab bucket and, in particular, to the head assembly of such bucket.

In various kinds of grab buckets, of the clamshell type, sheaves for the closing line are mounted on a. head pin which also serves for articulation of the corner bars, as shown by way of example in Patent 1,808,800 to W. M. Venable. This invention may be regarded as an improvement on that type of head, but is not necessarily limited to use in a lever arm bucket as there shown. In the construction shown in the patent referred to, a pair of scoops are pivoted together, each scoop having pivoted thereto a pair of corner bars extending upwardly to a common pivot, on which pivot closing sheaves also are mounted. A head casting or fabricated head structure is provided to enclose the sheaves and support leading-in guide sheaves or rollers, fastenings for cables, and to give the head of the bucket lateral stiffness. In the Venable patent referred to this head casting is bolted or riveted to one set of corner bars, and has bearings in both sides in which the head pin may turn. The other pair of corner bars is rigidly secured to the pin outside of the head casting.

With this construction, and other constructions that have been employed, difficulty has been experienced in maintaining a tight connection between the head casting and the corner bars to which it is secured by bolts, rivets, or the like. Regardless of the fastening means employed, it is found that they become loosened by the impact .to which they are subject when the bucket is dropped or otherwise subjected to heavy shocks in ordinaryuse. Furthermore, the lateral stiffness of the bucket at the head must be provided almost entirely by the head casting, and breakages occur occasionally, even where design, workmanship, and materials are of the best.

I have invented a head assembly which overcomes the aforementioned, and other objections. Instead of articulating the pin in the head casting, I articulate it in one pair of corner bars, and connect that pair of bars to the head casting by means of a pair of plates, one on eachside of the bucket head, secured by bolts orrivets. The

sheaves, as usual, turn on the head pin. .All'

stresses imposed on the head pin are transmitted to the corner bars without passing through the head casting. The head casting,-however, supports the guide sheaves and dead ends for operating lines, and adds lateral stiffness. The following detailed description of the invention refers to the accompanying drawings illustrating the preferred embodiment. In the drawings:

Fig. 1 is a side elevation of my novel head assembly;

Fig. 2 is a partial end view thereof;

Fig. '3 is a side elevation of the head casting;

Fig; 4- is a plan view thereof; and Fig. is an end view such as would be seen by looking on Figs. 3 or 4 from the left.

Referring now in detail to the drawings, a 5 head assembly in accordance with my invention, indicated generally at iii, comprises a head casting ll, side plates l2 secured thereto and depending therefrom, a pair of corner bars l3 secured to the side plates l2 and pivoted to one of the scoops of a grab bucket, a hinge pin i4 journaled in the eyes l5 at the ends of the bars l3, and corner bars i6 secured to the pin l4 and pivoted to the other scoop of the bucket. The bucket to which the invention as illustrated is applied, is of the lever arm type, the arms [1 and I8 being rigid with the bucket scoops and pivoted together at I9. The closing mechanism includes sheaves 2U journaled on the hinge pin 14 and sheaves 2i journaled on a shaft 22. The shaft 22 0 is journaled in bearings 23 carried by an assembly of plates 24 and angles 25 secured to the scoop to which the lever I8 is attached.

The head casting I lie shown in detail in Figs. 3

through 5. As there shown, the casting is gen- 25 erally box-like, having side walls 25 and 26, end walls 2? and 28, and a cross wall 29. The end wall 21 and cross wall 29 are bored at 30 to provide bearings for guide rollers 3! between which the closing line passes. Rounded lips 32 are 30 formed in these walls between the bearings for the rollers 3! to guide the closing line on tilting of the head casting relative to the vertical, Bearings 30* are formed in the side walls of the casting to support a cross roller 32 effective to guide the closing line into the righthand lip 32 on leftward tilting of the head assembly. The casting also has a socket 33 in which the end of the closing line maybe dead-ended. Bearings 34 are formed on the side walls of the casting to receive a pin 35 on which is pivoted a clevis 36. The holding line is attached to the clevis.

The side plates !2 are seecured to the side walls 25 and 26 of the casting by rivets 31, the side walls being drilled as at 38 to receive the rivets. As shown in Fig. 2, the corner bars l3 ex-. tend from the pin M at an oblique angle-thereto. The plates l2 are bent as at 39 so that the lower portions thereof will engage the sides of the bars I3 flatwise while the upper portions of the plates similarly engage the sides of the casting l I. The plates l2 and the bars l3 are suitably drilled to receive rivets 40 which are effective to secure the bars l3 to the casting ll through the plates l2.

The bars l6 have eyes 4| through which the pin M extends and the pin may conveniently be se-. cured to these eyes for rotation therewith in the eyes l5 of the bars E3. The side walls of the cast-- ing H are notched as'at 52 to clear the pin I4 and the eyes of the corner bars, and extend arch- 60.

wise over the latter. The width of the casting (i. e., the dimension perpendicular to the side walls) is a minimum, being only great enough to provide space for the desired number of sheaves between the eyes of the inner corner bars l3. This is an advantage since it permits the pin 14 to be made shorter than was required previously,-

and the diameter of the pin varies generally according to the length, to carry a given load.

A cross brace 43 is secured to each of the bars l3 and holds them rigidly in fixed relation to each other.

One of the advantages of the invention will be readily recognized when it is considered that the forces exerted longitudinally of the bars l3 and I6, when the closing line is taken up to pull the scoops together, are transmitted directly to the head pin H but are not applied to the casting ll. The latter, therefore, need be only strong enough to permit the lifting of the bucket by the closing line and to withstand such force as may be applied thereto by the dead-ending of the closing line in the socket 33. It is thus possible to effect a saving in the weight and cost of the casting H as compared to head castings as previously constructed. A downward pull on the sheaves 2!) causes a resultant downward thrust on each of the corner bars l3 and l 6 but no stress is applied to the head casting as a result of any pull applied to the sheaves. My casting, furthermore, is much stronger in resistance to the shocks received in ordinary operation and while the chance of loosening of the rivets, such as those shown at 3'! and 40, is considerably reduced by the invention, there is less danger of breakage of the casting than in the construction according to which the corner bars are rigidly connected to the casting. This is explained by the fact that the side plates l2 and the bend formed therein at 39 provide a certain limited flexibility in the connection between the head casting and the corner bars l3. The casting also assists in holding the corner bars I 3 in proper relative positions although the cross brace 43 is the principal reliance for this purpose. The reeving employed with a bucket embodying the invention may be the same as that previously used, i. e., with either three, four, or five parts of line, the number of head sheaves and the location of the dead-end of the closing line being determined by the character of the reeving. V

As already stated, the invention, while illustrated as applied to a grab bucket of the lever arm type, may also be applied to any bucket utilizing closing sheaves mounted on the head pin.

Although I have illustrated and described herein but a preferred embodiment of the invention,

it will be understood that changes in the construction and arrangement of parts disclosed may be made without departing from the spirit of the invention or the scope of the appended claims.

I claim:

1. A head assembly for grab buckets or the like including two bucket portions pivoted to each other and a pair of supporting bars pivoted to each bucket portion, said assembly comprising a generally box-shaped head casting, side plates secured to said casting and depending therefrom, the bars of one pair being secured to said plates, all said bars having alined eyes and a hinge pin extending through said eyes, a closing sheave journaled on said pin, and a closing line traversing said sheave, the eyes of said one pair of bars providing the sole supports for said pin when the bucket is suspended, the other bars being carried on said pin when the bucket is suspended, said bars lying at oblique angles to said pin, and said plates having portions lying at an angle to each other for engagement with the sides of said casting and said one pair of bars,

respectively.

2. In a grab bucket, a pair of scoops, a pair of corner bars pivoted to each scoop, said scoops being pivoted together, said bars being pivoted together on a common head pin, a sheave journaled on said pin, and a closing line traversing said sheave, a head casting extending archwise around said pin and spaced therefrom, side plates secured to said casting and to the bars of one of said pairs, whereby stresses setup on taking in said closing line are transmitted from said pin directly to said corner bars instead of to said casting. V p

3. A head assembly for a grab bucket including two scoops pivoted together, and a pair of supporting bars pivoted to each scoop at one end, with eyes in their other ends through which passes a hinge pin, a sheave journaled on said pin and a closing line traversing said sheave, said assembly comprising a pair of side plates secured to the bars of one scoop adjacent the eyes therein and extending upwardly beyond said eyes, and a head casting secured to the plates, extending archwise around said pin and eyes, and in stresstransmitting relation with said pin only through said plates, whereby stresses set up on taking in said closing line are transmitted from said pin directly to said corner'bars instead of to said casting.

4. In a grab bucket, two scoops each having a pair of corner bars pivoted on a common head pin, a sheave journaled on said pin, a closing line traversing said sheave, side plates secured to one pair of bars and extending upwardly therefrom, and a head casting secured to said plates, said casting having stress-transmitting relation with said bars solely through said plates, whereby stresses set up on taking in said closing line are transmitted from said pin directly to said corner bars instead of to said casting.

5. In a grab bucket, a pair of scoops pivoted together, a pair of corner bars pivoted at one end to each scoop, said corner bars having eyes at' their other end, a hinge pin extending through the eyes of all said bars, a sheave journaled on said pin and a closing line traversing said sheave, plates secured to the bars pivoted to one scoop, adjacent the eyes thereof, and a head casting secured to said plates but otherwise free of said pin, the 'eyes of said last-mentioned bars providing the sole support for said pin when the bucket is suspended, the other bars being carried on said pin when the bucket is suspended,

whereby stresses set up on taking in said closing line are transmitted directly to said corner bars and not through said casting.

6. In a grab bucket, a pair of scoops pivotedto- 'gether, a pair of corner bars pivoted at one end to each scoop, said corner bars having eyes at their other end, a hinge pin extending through the eyes of all said bars, a sheave journaled on said pin and a closing line traversing said sheave,

EDWARD L. HARRINGTON. 

